Distance-measuring device.



W. J. ASHCRAFT.

DISTANCE MEASURING DEVICE. APPLIUATION FILED JULY2,1912.

Patented June 9, 1914.

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W. J. ASHGRAFT. DISTANCE MBASURING DEVICE.

APPLICATION FILED JULY2,1B12.

Patented June 9,1914.

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Uren srarns PATENT ormoni.

WENDELL J. ASHCRAFT, 0F SHORT CREEK, WEST VIRGINIA, ASSIGNOR OIE' ONE-HALF TO L. W. MCCLURE, 0F SHORT CREEK, WEST VIRGINIA.

DISTANCE-MEASURING DEVICE.

Specification of Letters Patent.

Application filed July 2, 1912.

.Patented June 9, 1914. serial No. 707,207.

T0 all 'whom 'it may concern Be it known that I, VVENDELL J. Asncnar'r, a citizen of the United States of America, and resident of Short Creek, county of Brooke, and State of West Virginia, have invented certain new and useful Improvements in Distance-Measuring Devices7 of which the following is a specification.

This invention relates to distance measuring devices, and more particularly to an instrument whereby the distance between the instrument, or a sighting point, and a distant object may be determlned.

The primary object of the invention is to provide a simple instrument or apparatus for accurately indicating the distance loe-- tween a sighting point and a distant object, such distance being indicated and readable on the instrument either in terms of length or in terms readily translatable into terms of length.

A further object is to provide an instrument of the character mentioned which is especially adapted for use in surveying, being of such size and weight as to be conveniently transportable from place to place and being adapted to be readily and conveniently set up for use.

With these and other objects in view, the invention resides in the features of construction, arrangement of parts and coinbinations of elements which will hereinafter be fully described, reference being had to the accompanying drawings, forming' a part of this specification, in which- Figure l is a .rear elevation of the invention; Fig'. 2 an end elevation of the same; Fig. 3 is a slightly enlarged top plan view of the same; Fig. 4t is a section on the line 9 4, Fig'. 3; and Fig. 5 is a diagram illustrating the method of operation.

Referring to said drawings, in which like designating' characters distinguish like parts throughout the several viewsl indicates generally a horizontally disposed frame which may be of any appropriate form or design having a supporting stem 2, the latter being preferably of `an adjustable ball and socket type adapted for mounting upon a stand or tripod 3. A `table or plate 4t is rigidly mounted in a horizontal position 0n said frame and has its top face provided with graduations, as shown in Fig. 3, the purpose of which will presently be dscribed. Mounted on said frame adjacent to one end thereof so as to occupy a position at a direct right angle to the graduated plate 4 is a stationary telescope 5, a suitable upright fixed supporting bracket, as 6, being preferably provided therefor. L0- catcd in front of and parallel to said plate 4t and having' its opposite ends suitably mounted on the frame l is a stationary horizontal bar 7, preferably rectangular in cross section, having mounted thereon a longitudinally slidable member or slide-block 8 on which is pivoted, as shown at 9, the base member l()u of an angular supporting bracket 10 having rigidly mounted thereon a telescope ll which is adapted, in one position of the slide-block and bracket 10, to directly overlie said telescope 5.

When it is desired to determine or meas- 'ure the distance between two points, the instrument is mounted so that a plumb 12, carried by a line 13 in the vert-ical line passing through the objective end of the stationary telescope 5, stands directly over one of the points, which latter may be termed the sighting point, and so that the distant point or object is in theline of sight through said telescope 5. The movable telescope 11 having been previously adjusted to an angle with respect to the stationary telescope, so that moveu'lent thereof along the bar 7 a certain distance, as one inch, from the point in which the objective ends of `both are 1n the vertical line through the sighting point, will cause the lines of sight to intersect at a certain known distance, as l0() feet, from the sighting point, the said movable telescope is moved along said bar T until the distant object appears in the line of sight thereof. The distance between the points may then readily be determined by multiplying the known distance between the sighting point and the intersecting lilies of sight with a certain length of movement by the movement reading on the plate.

Referring specifically to Fig. 5, the telescopes 5 and l1 are shown in full lines in initial position with their objective ends in the san'ievertical line, the telescope ll occupying `such an angle with respect to telerespect to telescope 5.

scope 5 that movement of the latter the distance of one inch causes the lines of sight ct and b to intersect at a point A distant 100 feet from the sighting point B. To determine the distance from B to a distant object C, the telescope 11 is moved until its line of sight 0 intersects at said object the line of sight of telescope 5 focused on said object. Then, multiplying the known distance measuied by a given movement, that is, 100 feet to 1 inch of movement, by the length ofv movement indicated on the scale, 3 inches, it is found that the object C is 30() feet distant from the sighting point B.

The slide-block preferably bears thereon an arcuate scale 14 which, as is obvious, may bear degree indications showing the angle of inclination of the telescope 5, or may bear distance indications showing the distances from the vertical focal line through the sighting point to the intersecting lines of sight at different angles of inclination ascertained or indicated by a certain length of movement ofthe telescope 11. Asset screw 15, clearly shown in Fig. 4, is directed upward through a slot 16 provided in a plate 17 fixed on the slide-block and has its point seated in the under side of the base member 10EL of the supporting bracket 10, said set screw being adapted to be caused to impinge upon said plate 17 for locking said supporting bracket in adjusted position.

' As is obvious, the plate 4 may be graduated in inches and fractions thereof, as shown, for indicatingthe length of movement of the movable telescope 11 along the bar 7 or, it may have distances recorded thereon so that measured distances may be directly readable thereon, as when the telescope 11 is mounted at a fixed angle with To avoid the necessity for the useon plate 4 of graduations which, in order to be accurately readable in feet and inches, would necessarily be exceedingly minute and delicate on a plate of convenient length, a micrometer adjustment and indicating dial are provided. Said dial, designated 1S, is mounted upon a second slide-blocklf)V which is slidable upon the bar 7. A screw 20 with micrometer threads and having its point swiveled in a socket-post 21, carried by the slide-block 8, is threaded through a sleeveQQI fixed on a post 23 carried by the slide-block 19. Said screw has an index finger or indicator 24 adapted to rotate over the face of said dial as the screw is turned.

" In practice, the telescope 11 is moved toV the point where its line of sight intersects or converges with that of the telescope 5 directly at the distant object. Then, provided the index finger or indicator 25 carried at a suitable point, as on the slideblock 8, does not indicate a graduation on the plate 4 which permits an exact reading, the slide-block is moved forwarder backward, as preferred, to the nearest graduation which does permit of suchL reading. Then, a set-screw 26 carried by the slide-V lblock 19 is set to impinge on bar 7 for main-V taining or locking said slide-block in fixed position, whereupon, by manipulation of the micrometer screw 20, the slide-block 8 is moved until the lines of sight again intersect on the distant object. By counting the number of revolutions and fractions thereof made by the indicator 24 over the face of the dial 18, the number of feetV and inches to be added or subtracted, as the case may be, from the reading taken lon the plate 4, the distance is accurately determined. As depicted in Fig.- 4, the dial is graduated to indicate 3 feet for each revolution of the micrometer screw; hence, assuming that three and one-half revolutions of said screw is required to move the telescope 11 forward to the point where its line of sight intersects at the object with the line kof sight of the telescope 5, the distance reading ascertained on the plate 4 would require to be increased by 10 feet 6 inches.

It will be understood that variousy slight modifications. in theconst'ruction of the instrument herembefore described may be resorted to without departing from the general spirit or scope of the invention as defined in the appended claim. It will also be obvious that various types of graduations whereby distancesV may be directly indicated on the instrument itself, or from which they may be readily computed,.may suggest themselves to thoseV skilled Vin the art. Hence, l do not desire to be 'understood as limiting myself to the precise structural details or' to the type of graduations Vherein shown and described.

Having thus described Vmy invention, what I claim as new, and desire toV secure by Letters Patent, is

In an instrument for measuring distances,

a support, a bar mounted on said support, a telescope fixed at a right angle to said bar, a slide-block embracing` and slidably mounted on said bar,- a second telescope pivotally mounted on said slide-block and, when occupying Zero position,V having` its line of sight inteisectingthat of the fixed telescope at a known distance from the sighting point, an index finger carried by said slide-block, a plate provided with a scale adapted to be traversed by said finger and on which, when f said movable telescope is adjusted to cause its line of sight to intersect that of the fixed telescope on a distant object, is indicated the approximate distance of such object from the sighting point, said slide-block being provided with a calibrated scale wheie-V on the angular adjustment of said movableb telescope is indicated, a second slide-block In testimony whereof I affix my signature slidably mounted on said bar, an indicating in presence of two subscribing Witnesses.

dial mounted on said second Slide-block, a WENDELL J. ASHCRAFT. micrometer screw connecting said slide- Witnesses:

5 blocks, and means for fixing said second H. E. DUNLAP, slideb1ock with respect to said bar. L. D. MORRIS.

Copie: of this patent may be obtained for live cents each, by addressing the Commissioner of lPatentl, Washington, D. C. 

